var imageArray = new Array();

function swapimages(image, imageurl)
{
	var storedImage = imageArray[imageurl];
	
	if(storedImage)
	{
		image.src = storedImage.src;
	}
	else
	{
		imageArray[imageurl] = new Image();
		imageArray[imageurl].src = imageurl;
		
		image.src = imageArray[imageurl].src;
	}
}

function navState(navNameOn)
{
	var navImage = document.getElementById(navNameOn);
	swapimages(navImage, '/images/navigation/' + navNameOn + '_on.gif');
	navImage.onmouseout = null;
}